Electronics Stereotypical 3 wire bomb

Being an airsofter i am always wanting to make the game as intresting as possible. I currently run my own private games in my forest with about 20 of my friends.

We had an idea for a new scenario for us to play (i wont go into details) and we want to make a bomb! Well not so much as make a bomb but a classic 3 wire trigger mechanism.

We want it to set off a camera flash or something because explosives are just stupid.

Any help will be appreciated.

Regards Inafinus

 

and you want it to flash when you cut the WRONG wire, which is selectable?

 

Well no. One wire that would "disarm" it. The other two would set it off. Sorry i didnt explain clearly.

I would also like to put a timer on it that would set off the flash after a certain time. But that is optional.

 

So basically, make it have a "sense" wire, and hook it up so that when either power or ground goes, a cap discharges into the flash...

 

you could do that with a camera flash from a disposable camera, a battery for that, a dpdt relay or two and a 12v or 6v lantern battery for the relay.

The flash has 2 contacts that you connect to start charging, and 2 that you connect to fire the flash.

using one set of NO contacts you, connect the charge wire. using the other set of NC contacts you, connect the 'fire' contacts. So when the power is turned on to the relay, the battery is connected to the relay though the 2 'wrong' wires, connected in series. So arming it, turns on the relay, charges the flash, and it waits.

They come to difuse it start snipping, and if they get a wrong one, it turns off the relay, disconnects the charge contacts, which is fine, and connects the fire contacts, making the flash go off.

You could add a second NO relay, which when the power is turned off to it, it would disconnect the flash tube from the capacitor so it would be disarmed. The power wire for this one would be the 'correct' wire.

 

Just a thought for the effect...you could have it detonate some firecrackers as well. It shouldn't take much of an electrical charge to set them off, although I've never tried. This way you would have audible as well as visual indication that the "bomb" went off.

 

the perfect way to get arrested by the Yard for terrorism. don't do this.

 

LOL. That will not get you arrested, what a comment.

 

Mey. I dont want to get into **** for this. It is a bit of a risky subject as it is so im not going to push my luck.

So i realy only need a disposable camera and some relays. That can be very easily done. I dont quite get what you mean about the NO contacts and NC contacts. I looked for it on uncle google and it just came up with some locks =s

And what about the timer. I would probably have to program a PIC for this eh?

 

NO = Normally Open.
NC = Normally Closed.

 

use a 555timer 8 pin chip and change the timings using resistors by varying the voltage inputs.

 

I did think that. And say i wanted the timer to go on for half an hour. Would this be viable?

 

With A PIC you can use those big red 7 segment led displays. A must for every bomb that has a timer

 

That's perfectly do-able with a 555 or pic, but much easier to do with the first.

The real problem is that a 555 won't really be able to show you the time-left, well, explicitly anyway.

 

Hey funny you ask, I was checking through ZapWizards webpage yesterday and there was a simliar sort of thing you wanted. We had this discussion a while ago. Will find a link for you.

edit:
from http://www.zapwizard.com/Guides/Schematics/index.html
http://www.zapwizard.com/Guides/Schematics/555-Bomb.gif

 

you had your head under a log for a while, have you?

 

I like the idea of the 555. Sure the display would be nice but its not completley nescisary.

And what about setting off a fire cracker. When i get back from school i will post a link of these electronicallyu set of "flash bangs" that you can get for CQB (Close quarter combat) airsoft.

http://www.airsoftscotland.com/acatalog/Fashbangs.html

 

555's are only acuracte upto 20mins. if you want to set off fireworks look at whats used in model rockets... they have two wires with a thin layer of explosives in between them:

http://www.modelrockets.co.uk/shop/index.php?cPath=28_46&osCsid=6158424ac3e82e54f38e0c7672851106

you can make a binary counter circuit and use a 555 astable to say send a pulse to it every minuite (Look up if 555 astables can have that long timing periods tohugh!) and then set off the egnighter when the counter has got upto a certian number, for construction of binary counters from D type flip flops look here:

http://www.ikes.freeserve.co.uk/fur.htm
and get the AS further electronics support booklet

Then if you want to display you could use a binary to decimal device and then a 7segment display driver

.... OMG I just got triked into designing a bomb detonator didn't I :O

 

that is exactly how i would have done it, and exactly the way I did do it for my AS-electronics project. Not so sure about the 20min accuracy comment though mine went to 99:59.99 and was only a second or 2 out which isnt too bad. Guess it depends on how you design it, my only gripe is the size of the circuit. Its not huge but mine took up 4 prototype boards so if sapce is a major issue you might have to look elsewhere.